Recovering GRUB after reinstalling Windows

Use any LiveCD (or other route) to access a Grub command-line and fix the MBR:

1. Boot into a LiveCD
2. Open a terminal
3. Open the GRUB Command-line utility by typing

sudo grub

4. Find where Grub is. If this gives a few different answers then you will need to find the correct one, perhaps by trial-and-error.

find /boot/grub/stage1

5. Tell GRUB which partition to tell the MBR your Grub is on by entering

root (hdA,B)

The coordinates A,B are where 'A' is the hard-drive number, starting at 0, and 'B' is the partition number, starting at 0. For example, if Ubuntu was installed on the second partition of the first hard-drive, the command should be

root (hd0,1)

6. Tell GRUB which drive's MBR to fix

setup (hd0)

Replace 0 only in the extremely unlikely event that your bios does not use the first hard-drive as the boot device. Typically Ubuntu might be on any drive but the bios will almost always go to the first drive's MBR to find out where to find the boot-loader.

7. Leave the GRUB Command line

quit

and reboot.

Sumit gupta
CSE Deptt.
NIT Durgapur